One of the big moments of the State of the Union address was President Barack Obama’s call for “high-quality preschool” for 4-year-olds.

Nobody was happier at the idea than Walter Mondale, the former vice president.

“This is going to be wonderful,” he said in a phone conversation. His delight was sort of inspiring. If I had been down the road Mondale has traveled, my mood would have been a little darker.

In 1971, when he was a senator, Mondale led the congressional drive to make quality preschool education available to every family in the United States that wanted it. Everybody. The federal government would set standards and provide backup services like meals and medical and dental checkups. Tuition would depend on the family’s ability to pay.

And it passed! Then Richard Nixon vetoed it, claiming Congress was proposing “communal approaches to child rearing.” Now, 42 years later, working parents of every economic level scramble madly to find quality programs for their preschoolers, while the waiting lines for poor families looking for subsidized programs stretch on into infinity.

And Obama is trying, against great odds, to do something for 4-year-olds.

People, think about this for a minute. We have no bigger crisis as a nation than the class barrier. We’re near the bottom of the industrialized world when it comes to upward mobility. A child born to poor parents has a pathetic chance of growing up to be anything but poor. This isn’t the way things were supposed to be in the United States. But here we are.

Would it be different if all the children born over the past 40 years had been given access to top-quality early education — programs that not only kept them safe while their parents worked but gave them the language and reasoning skills that wealthy families pass on as a matter of course?

We’ll never know.

Mondale’s Comprehensive Child Development Act was a bipartisan bill, which passed 63-17 in the Senate. It was an entitlement, and, if it had become law, it would have been one entitlement for little children in a world where most of the money goes to the elderly.

“We came up with a lot of proposals, but the one we were most excited about was early childhood education. Everything we learned firmed up the view this really works,” Mondale said.

The destruction of his bill was one of the earliest victories of the new right.

“The federal government should not be in the business of raising America’s children. It was a political and ideological ideal of great importance,” Pat Buchanan once told me.

He was working at the White House when the bill reached Nixon’s desk, and he helped write the veto message. He spoke about this achievement with great pride.

The saga of the demise of the Comprehensive Child Development Act is an excellent explanation of why Obama was prepared to go through so much political trauma to pass health care reform, even when many of his own party members were begging him to drop back, do something less earth-shaking and wait for a better moment.

The better moment might never come.

After Gerald Ford became president, the early childhood education bill’s supporters tried to resurrect the plan. They had hardly done anything besides agree that they probably ought to wait until after the 1976 election, when they were hit with a political tsunami. Members of Congress started getting hundreds and hundreds — sometimes thousands and thousands — of hysterical letters accusing them of plotting to destroy the American family.

This was before constituent email, when that kind of outpouring was shocking, particularly since a number of the writers seemed to believe that Congress was plotting to allow children to organize labor unions and sue their parents for making them do chores.

“That was really the beginning of the Tea Party. The right wing started to turn on this thing viciously,” Mondale said. “They said it was a socialist scheme. They were really pounding the members of Congress, and a lot of people got cold feet.”

Nobody really knew where it was all coming from. A reporter for The Houston Chronicle traced the hysteria back to a man in Kansas who had written the leaflet, based on information he’d received from a revival in Missouri, which he told the reporter he had since learned was almost all completely wrong.

But that was it. Later, people would begin proposing modest preschool programs, particularly for the offspring of poor women who were required to work after the repeal of welfare entitlements in the Clinton years. But there would never again be a serious attempt to guarantee all American families access to quality early education and after-school programs.

The president proposes doing something for 4-year-olds. This is a great idea. Mondale is certainly enthusiastic. But still.